[jdk17u-dev] RFR: 8280885: Shenandoah: Some tests failed with "EA: missing allocation reference path"

[Aleksey Shipilev]

Clean backport to fix Shenandoah barrier handling.

Additional testing:
 - [x] New test on Linux aarch64 fastdebug, does not fail without the fix for some reason, probably missing iterative EA, JDK-8276455)
 - [ ] Linux aarch64 fastdebug `tier1` with `-XX:+UseShenandoahGC -XX:ShenandoahGCMode=iu`
 - [ ] Linux aarch64 fastdebug `tier2` with `-XX:+UseShenandoahGC -XX:ShenandoahGCMode=iu`

-------------

Commit messages:
 - Backport ab638341de164965e06bb1d59808670260916b82

Changes: https://git.openjdk.org/jdk17u-dev/pull/1537/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1537&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8280885
  Stats: 75 lines in 2 files changed: 74 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1537.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1537/head:pull/1537

PR: https://git.openjdk.org/jdk17u-dev/pull/1537